Sofa



FIG. 1 is a top, front and left side perspective view of the sofa;

FIG. 2 is a top plan view of the sofa;

FIG. 3 is a front elevational view of the sofa;

FIG. 4 is a rear elevational view of the sofa;

FIG. 5 is a left side elevational view of the sofa; and,

FIG. 6 is a right side elevational view of the sofa.

The broken lines shown in FIG. 1 are for environmental purposes only andform no part of the claimed design.

The ornamental design for a sofa, as shown and described.